Analog Integrated Circuits and Signal Processing

, Volume 82, Issue 2, pp 423–430 | Cite as

A variable-gain superregenerative amplifier controlled by duty-cycle for signal conditioning

  • Fernando Rangel de Sousa
  • Roddy Alexander Romero Antayhua


In this paper, a variable-gain amplifier (VGA) adjusted by the duty-cycle of a control signal is presented. This circuit is based on the superregenerative concept created by Armstrong back in the 1920s. The technique selected allows a fine control of the gain to be performed without any D/A converter at the interface between the digital control and the amplifier, as generally seen in other VGAs. An integrated-circuit version of the VGA was fabricated in a standard \(180\,{\mathrm {nm}}\) CMOS process, aimed at achieving low-power consumption. Simulation results show a maximum gain of \(45\,{\mathrm {dB}}\) within a \(900\,{\mathrm {mV}}\) linear range, \(0.5\,\%\) THD and a power consumption of \(6.4\,\upmu {\mathrm {W}}\). Measurements on the chip were performed and the results corroborate the simulations.


Signal conditioning Superregenerative amplifier Variable gain amplifier Analog design 



The authors would like to thank CNPq and INCT NAMITEC. Also, the authors are thankful to Gabriel Manoel Da Silva for helping with the VGA measurements.


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Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • Fernando Rangel de Sousa
    • 1
  • Roddy Alexander Romero Antayhua
    • 1
  1. 1.Radio Frequency Laboratory, Department of Electrical and Electronic Engineering Federal University of Santa Catarina (UFSC)FlorianópolisBrazil

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